1. Field of the Invention
The invention conceptually pertains to the control of engines, and relates to fuel control methods for multi-cylinder engines in which the amount of fuel that is supplied from fuel injection valves to a plurality of cylinders is controlled individually, fuel injection amount control methods, and engine operation state discrimination methods using the same, of an engine (particularly an engine with a supercharger) that controls an injection amount of fuel to be injected from the fuel injection valves, propulsion apparatuses for multiple engines in which propeller shafts are each individually connected to a plurality of engines, and crash astern fuel injection control methods for marine engines with a reduction and reversal device for abruptly stopping the ship when it is moving forward.
2. Description of the Art
Multi-cylinder engines such as diesel engines generally are furnished with an electric fuel injection apparatus that electrically controls fuel injection (that is, performs fuel injection amount control and injection timing control) according to the operation state of the engine in order to further improve its operability (for example, see Patent Document 1). In such electric fuel injection apparatuses, the amount of fuel that is supplied from the fuel injection valves to the cylinders of the engine is individually controlled.
Such electric fuel injection apparatuses are conventionally known to include boost compensators that limit the fuel injection amount from the fuel injection valve in accordance with the amount of air that is sucked into the engine, so as to reduce the black smoke that is discharged from the engine (for example, see Patent Document 2).
The electric fuel injection apparatuses described above are used in engines furnished in marine vessels, for example. Conventionally, when a plurality of engines are installed in a marine vessel, for example, it is known that propeller shafts each having a screw propeller at one end are individually connected to the engines and a single regulator lever is used to synchronously adjust the revolution of the propeller shafts of the engines (for example, see Patent Document 3).
Further, in marine vessels, in general, an operation called a crash astern in which the clutch is switched from forward to reverse is performed to abruptly stop the marine vessel. When executing a crash astern, there is a risk that a load that is too large in magnitude will be applied to the engine and cause it to stall. This is because the actual revolution of the engine drops when the clutch is switched from forward to reverse. Thus, to prevent stalling, an engine revolution that functions as an engine stall limit is set for each magnitude of the actual revolution of the engine during execution of the crash astern, and when the speed falls below that engine revolution, the clutch is put into neutral to lower the burden on the engine and allow the actual revolution of the engine to recover, and once this has recovered to a certain degree, then the clutch is switched to reverse.
However, this method requires that the clutch is switched to reverse after the actual revolution of the engine has increased by a certain degree, and thus a considerable amount of time is necessary before the ship comes to a stop.
For this reason, conventionally, when a clutch astern is executed by switching the clutch from forward to reverse in order to stop the ship when it is traveling in the forward direction, control is performed so that the clutch hydraulic pressure is such that the engine does not stop due to the magnitude of the actual revolution of the engine, and this allows the moving ship to stop abruptly without stalling (for example, see Patent Document 4).    Patent Document 1: JP H4-59458B    Patent Document 2: JP 2001-227382A    Patent Document 3: JP 2001-128388A    Patent Document 4: JP 2001-71995A